7?T 

15     1916 


DATA  ON  VENTILATION 


Supplementary  to  Section  II  of  "Scientific 
Office  Management"  by  W.  H.  Leffingwell 


A.  W.  SHAW  COMPANY 

CHICAGO  NEW  YORK 

LONDON 


COPYRIGHT,  1917,  BY 
A.  W.  SHAW  COMPANY 

PRINTED  IN  U.  8.  A. 


-r  iA  1 b^ 


DATA   ON  VENTILATION 


The  story  of  the  Black  Hole  of  Calcutta  is  familiar  to  all 
of  us,  but  its  lesson  has  not  yet  been  universally  learned.  The 
necessity  of  fresh  air  has  been  shown  by  the  tuberculosis  agita- 
tion and  nearly  everyone  knows  that  pure  fresh  air  is  an  abso- 
lute necessity  for  life.  Many  business  men  have,  however,  not 
yet  applied  to  their  offices  the  logical  conclusion  from  these  well- 
known  facts.  If  fresh  air  is  necessary  for  life,  it  must  certainly 
be  necessary  for  good  work. 

There  have  been  many  contradictory  theories  of  ventilation, 
none  of  which  however  has  denied  the  necessity  of  pure,  fresh 
air  for  efficient  work.  They  have  all  revolved  around  the  ques- 
tion as  to  just  what  were  the  harmful  elements  in  impure  air. 

Through  the  work  done  by  municipalities  in  ventilating 
schoolrooms,  the  methods  of  thoroughly  ventilating  large  rooms 
occupied  by  many  people  have  for  many  years  been  well  known. 
Even  so,  this  knowledge  has  perhaps  rarely  been  used  outside 
of  schoolrooms  and  theaters,  where  ventilation  may  be  com- 
pulsory. 

Kendall  Banning  tells  about  one  company  which  found  that 
every  cold  contracted  by  its  employees  cost  twenty- four  dollars. 
It  is  well  known  that  colds  are  often  due  to  improper  venti- 
lation.* Another  company,  manufacturing  straw  hats  in  Bal- 
timore, found  that  the  percentage  of  sickness  during  two  win- 
ters was  27.5.  An  investigation  revealed  defects  in  the  ventila- 
tion and  heating  system.  Proper  ventilation  was  provided  and 
the  percentage  of  sickness  dropped  to  seven. 

Although  one  manager  thinks  the  estimate  of  four  per  cent 
increase  in  efficiency  is  perhaps  too  low,  let's  suppose  there 

*  "Figures  to  Prove  That  Ventilation  Pays,"  by  Kendall  Banning,  SYSTEM,  Volume 
XXX,  No.  3 

(i) 


were  one  hm:dr£(l  clerks  getting  an  average  wage  of  six  hundred 
dollars  a  year,  which  means  an  annual  payroll  of  sixty  thousand 
dollars.  Four  per  cent  of  this  would  be  two  thousand  four 
hundred  dollars,  a  sum  sufficient  to  pay  for  a  very  elaborate 
ventilating  system. 


Curve 
Nos.1 
and  2 


Curve  No.  1  -  Mental  Multiplication  -  Net  No.  of  problems  done  x  10 
Curve  No.  2-  Typewriting  -  No.  of  Lines  x  10 
Curve  No.  3-  Heavy  Reading -Pages  read 


HOW  ATMOSPHERIC  CONDITIONS  AFFECT  OFFICE  WORKERS 

The  graph  shown  above,  together  with  the  one  on  the  next  page,  shows  the 

results  of  tests  made  by  the  New  York  State  Commission  on  ventilation.    One 

of  the  conclusions  arrived  at,  as  indicated  by  this  graph,  is  that  the  air  a  worker 

breathes  has  a  direct  bearing  upon  his  capacity  as  expressed  in  the  output 

It  is  quite  true,  of  course,  that  many  offices  are  located  in  old- 
fashioned  buildings  not  provided  with  ventilating  systems.  For 
these  it  is  perhaps  well  to  mention  a  few  makeshifts  that  are 
certainly  better  than  nothing  at  all,  if  renovating  is  considered 
too  expensive. 

First  is  the  electric  fan.  It  has  been  demonstrated  that  air 
that  is  in  circulation  is  much  better  than  stagnant  air.  The  one 
drawback  to  the  electric  fan  is  that  it  also  stirs  up  particles 
of  dust  under  certain  conditions. 

Then  there  is  the  window  ventilator.  The  window  itself  as 
a  ventilator  is  lacking,  but  there  are  ventilators  which  deflect 
the  cold  air  upward.  By  leaving  the  window  open  a  few  inches 

(2) 


fresh  air  is  admitted.  Fresh  air,  however,  is  not  always  pure 
air,  especially  in  large  cities.  Perhaps  another  problem  to  be 
met  in  using  ventilators  of  this  sort  is  that  on  cold  days  the 


2,000 


T=756 
Stagnant 


T=68° 

Stagnant 


T=75° 
Air  Supply 


T=68° 
Air  Supply 


AIR  AND  THE  INCLINATION  TO  WORK 

A  group  of  men  on  whom  the  tests  were  made  did  37%  more  of  precisely  the 
same  work  at  68  degrees  than  they  did  at  86  degrees  under  exactly  similar  con- 
ditions.    This  finding  would  seem  to  warrant  the  conclusion  that  a  temperature 
of  68  degrees  is  perhaps  the  most  desirable  in  an  office 

(3) 


employees  sitting  next  to  them  often  close  them  because  the  cold 
air  is  too  uncomfortable. 

Perhaps  one  of  the  most  effective  makeshift  ventilators  is  a 
simple  exhaust  fan  which  exhausts  the  stagnant  air  in  the  room. 
This  air  must  be  replaced  hy  other  air  which  comes  in  from  the 
outside  at  every  opportunity,  through  the  windows  and  doors, 
but  does  not  come  in  at  an}r  one  place  in  sufficient  volume  to 
cause  uncomfortable  drafts. 

A  comparatively  cheap  ventilating  system  is  one  which  pumps 
in  enough  fresh  air  from  the  outside,  passes  it  over  steam  coils, 
and  heats  it  before  it  enters  the  room.  A  system  like  this, 
capable  of  heating  and  ventilating  an  office  of  one  hundred 
people,  can  be  installed  for  a  surprisingly  small  sum. 

Here  is  an  interesting  list  of  resolutions  passed  by  the  Chi- 
cago Commission  on  Ventilation,  which  reduced  its  findings  to 
specific  terms  by  means  of  them : 


1.  That  carbon  dioxide,  as  encoun- 
tered in  working  practice,  is  not  the 
harmful  agent  of  major  importance  in 
expired    air    or    air    otherwise    con- 
taminated. 

2.  That  a  temperature  of  68   de- 
grees Fahrenheit  with  a  proper  rela- 
tive humidity  is  the  proper  maximum 
temperature  for   living   rooms   artifi- 
cially heated. 

8.  That  in  the  present  state  of 
knowledge  it  is  impossible  to  designate 
all  harmful  factors  in  or  associated 
with  expired  air. 

4.  That  the  principle  of  ventilation 
by  currents  is  preferable  to  the  prin- 
ciple of  ventilation  by  dilution. 

5.  That    for    adequate   ventilation, 
smaller   volumes   of   air   suffice   when 
introduced    by    currents    than    when 
introduced  by  dilution. 

6.  That   ventilation   which   utilizes 
the  principle  of  convection  in  produc- 
ing   currents    is    more    effective    and 
economical  than  that  which  neglects 
this  principle. 

7.  That    upward    ventilation    cur- 
rents in  crowded  rooms  are  desirable, 
provided  the  sources  of  air  supply  are 
free  from  contamination. 

8.  That  in  making  use  of  upward 
ventilation,  attention  should  be  given 
to  the  counteracting  of  wall  and  win- 
dow chill. 

9.  That  in  those  processes  of  manu- 
facture   where    considerable    CO,    is 


liberated,   the   CO,   content   is   not   a 
proper  index  of  air  pollution. 

10.  That  for  the  removal  of  kitchen 
odors,  body  odors,  stable  odors,  and 
other  odors  associated  with  heat  pro- 
duction,  upward   ventilation   is   more 
efficient  than  downward  ventilation. 

11.  That  the  delivery  of  a  certain 
volume  of  air  per  unit  of  time,  per 
occupant,  into  a  given  space  does  not 
necessarily   constitute   ventilation. 

12.  That   air   which   is    introduced 
into  an  occupied  room  in  such  a  way 
that  it  strikes  the  occupants  should  be 
not  lower  in  temperature  than  60  de- 
grees Fahrenheit. 

13.  That    heating    and    ventilating 
are  two  distinct  problems,  and,  there- 
fore,  the  installation  of  heating   and 
ventilating  systems,  whether  separate 
or    combined,    should    be    such    that 
neither  system  shall  interfere  with  the 
efficiency  of  the  other. 

14.  That   from    the   standpoint   of 
health,  relative  humidity  is  one  of  the 
important  factors  in  ventilation. 

15.  That  efficient  air  cleaning  de- 
vices  are  desirable  in  all  ventilating 
installations  where  the  air  supply  is 
liable  to  be  contaminated  by  dust  or 
other  objectionable  matter. 

16.  That  the  bacterial  content  of 
the  air  is  an  important  factor  in  all 
ventilation,  and  bears  a  direct  relation 
to  the  source  and  quantity  of  the  air 
supply. 


(4) 


I  U     I 


Oaylord  Bros. 

Makers 
Syracuse,  N.  Y 

Mr.  JAM.  2|  .1 


University  of  California 
Richmond,  CA  94804-469* 


4  days  prior  to  due 


DD20  15M  4-02 


